Or he was playing a cash game until 6:00 a.m. and knew he wouldn't be on his A game, so he showed up late to catch up on sleep, thus improving his tournament EV. Of course this could only be true if he was hours late, not 15 minutes, as I doubt 15 minutes sleep would make much difference for anybody.

After submitting my hypothesis, I think it's just because he had it set up. What are the odds that ESPN just happened to have a camera in front of the Rio to show Phil arriving in his limo. He set it up to get more 20 year old frat boys worshipping at the altar of bad boy Phil, thus improving his lifetime EV.